Internal-combustion engine



ec.. 24, @929. c. c. MINTER 1,741,032

INTERNAL COMBUSTION ENGINE I Filed June 8. 1925 Patented Dec. 24, 1929 NlTED STATES PATENT @FFICE INTERNAL-COMBUSTION ENGINE Application filed J'une 8, 1925. Serial No; 35.704.

My invention relates to internal combustion engines, and it relates more particularly to means for accelerating the reactions which occur in the explosive charge upon ignition thereof in the combustion chamber of such an engine.

It is well known that the velocity of propagation of the flame in a combustible mixture, such as employed in internal combustion engines, varies with the air-fuel ratio. Very lean and very rich mixtures burn rather slowly, and the velocity of propagation reaches a maximum at a certain intermediate airtuel ratio which depends on the nature of i5 the fuel. When ordinary gasoline is used in an internal combustion engine having the usual smooth-walled cylindrical type of combustion chamber, this maximum occurs at an air-fuel ratio which is still too rich for eco- 2o nomical operation of the engine, the reactions taking place with a quantity of oxygen insuiicient `lor complet-e combustion and approximately thirty per cent of the fuel escaping complete combustion and appearing in. the

exhaust gases as carbon monoxide and hydrogen. Notwithstanding the waste involved, the use of such rich mixtures is wellnigh universal in the operation of vehicles equipped with internal combustion engines,

3C due in the main to traiiic conditions in congested areas which demand quick acceleration and which can be obtained only by the use of rich mixtures which burn more rapidly than lean, economical mixtures.

12 A primary object of the present invention 5U It is well known that the velocity of reactions in the gaseous phase is much slower in the bodyy of the gas itself, than in the portion of the gas in contact with the walls ot the containing vessel. In other words, gaseous reactions are accelerated by contact with solids, and in most cases the accelerated action is purely a surface eiiect. This principle of accelerated action by contact of the charge with a solid metallic substance is employed 1n iny present invention, the surface contact means being, of course, too inactive to produce ignition but active enough to accelerate combustion.

In the case of combustible mixture of gasolene vapor and air as customarily employed in internal combustion engines of the prior art, the mixture is usually ignited at one point adjacent the cylinder wall by an electric spark which raises the temperature of a small portion of the mixture to a suliicient degree to start the reaction, and since heat is liberated by the reaction, adjacent portions of the mixture are ignited and the flame is thus propagated by successive steps through the entire volume of the charge. 'It is therefore apparent that in the usual smooth-walled cylindrical type of combustion chamber, most of the reactions take place in the gaseous phase without contact with a solid surface and simply by a step-by-step propagation of the ame from the initial point ofthe reaction adjacent the cylinder walls inwardly throughout the entire volume of the charge. Under these circumstances, the progress of the reaction is slow, comparatively speaking, especially with lean and extremely rich mixtures, attaining its maximum velocity, as already stated, with mixtures still too rich for economical use.

My invention contemplates surface-contact means providing an extension of surface so distributed through the cubical contents of the combustion chamber as the piston nears and completes its compression stroke that no relatively large portion of the charge is out of' contact with that surface.

I am aware of the devices of the prior art for acceleration of combustion of the charge by changing the heat and vapor or gaseous conditions of the charge itself, such as heat absorbingland radiating elements, Vaporizing plates, etc., extending into the combustion chamber by attachment to the interior head-wall of the cylinder or to the upper face of the piston. The sole purpose of such devices and the sole results attained,I` however, have been -to very substantially increase the heat of the charge and to more perfectly vaporize or gasify its fuel constituent upon the compression stroke and before ignition, a-ny increased surface exposure of metal to the charge being incidental and from the very nature and objects of the heating devices not so distributed within the combustion chamber and throughout the charge as to function as a surface-contact means under the principles contemplated by my invention. Such devices of the prior art, while improvingthe conditions of the charge for combustion, still present the charge on the compression stroke confined as one body, or with a' relatively large portion so confined, between outer boundary metallic surfaces, so that the surface contact is only on the outer layer of the body of the charge and most of the reaction, that inwardly through the charge, takes place in the gaseous phase without contact with any solid surface.

Not only in the distribution of the metallic surface throughout the body of the charge upon the compression stroke of the engine, but also in another important respect, my invention contemplates a departure from and certain resulting advantages over the priorart devices referred to. In the prior art devices, the heating and radiating elements, vapori'zing plate, etc., are relatively large and massive bodies thermally insulated from the piston or cylinder walls or attached thereto through supports or connecting elements of reduced cross section for the purpose of thermal insulation or reduction of thermal conductivity, so as to store up in these bodies the heat of'explosion and deliver the saine to the new charge. IVhile certain advantages, hercinbefore mentioned, have been realized by these devices, there has been the attendant disadvantage of 'an excessive heat of compression, requiring a reduction'of pressure of the compression stroke to avoid preignition. My invention, on the other hand, contemplates no relatively large body or bodies of metal having great heat. absorbing and retaining capacity, but rather an extended metallic surface distributed throughout the charge on the compression stroke, with a minimum mass or body of metal and so disposed that heat is readily conducted therefrom through the piston or cylinder walls, the arrangement infact being such that on the compression stroke, the heat of compression will not be as great as inl even the conventional smooth-walled and unrestricted combustion chamber, because of the greater cooling effect of the larger metallic surface. Consequently higher compressions can be, and desirably are, used, the higher compression balancing the slight cooling ef- ,fect of the greater surface exposure referred to.

The foregoing objects and principles of my invention as well as other objects and advantages thereof, will more fully appear from a concrete embodiment thereof hereinafter described and illustrated in the accompanying drawings. It is to be understood, however, that the concrete embodiment shown and described is merely illustrative and that other specific embodiments and modifications of the present one may be made within the broad scope of my invention and as defined in the appended claims.

In the drawings:

Fig. l is a central longitudinal sectional view throughI the cylinder and associated parts of an internal combustion engine presenting one concrete embodiment of my invention; and

Fig. 2 is a cross-sectional view on the line Q-- of Fig. l looking in the direction of the arrows on Fig. 1.

A conventional type of L-head engine is shown, the engine cylinder being indicated b v the numeral 1, water jacketed as shown at 2, having a charge inlet valve 3 mounted in the lateral projecting valve casing 4, provided with a charge inlet conduit o and a passage 6 leading to the combustion chamber 7 between the cylinder head 8 and the piston 9. The usual type of spark plug is indicated at l0 projecting through the cylinder head into the combustion chamber, and the exhaust port is indicated at l1. All of these parts are ofthe usual or any desired construction, constituting in themselves no part of my invention, and it is to be understood that my invention may be embodied in or used with any type of internal combustion engine depending for its operation on an explosive charge of hydrocarbon and air or the like suporter of combustion, although the invention 1s particularly applicable to internal combustion engines using a charge mixture of air and gasoline.

In the present illustrative embodiment of the invention, the surface-contact means for acceleratingthe reactions which occur in the gaseous phase in the charge upon compression and ignition thereof, takes the form of surface extensions from the interior head wall of the cylinder and the opposite free face of the piston into the combustion chamber formed therebetween. v

These surface extensions are constituted by metallic fins, nodes or protuberances, preferably cast integral with the cylinder head and piston, respectively, massive enough to withstand the forces of compression and explosion of the charge without their breakage while at the same time relatively slen- 1,741,esa

der and elongated and tapering somewhat from their base to their free ends, andproriding a maximum surface presentation to the charge with a minimum possible mass or body.

The `fins, nodes or protuberances projecting from the cylinder head are indicated by the numeral 12 and those from the opposed face of the piston by the numeral 13. The fins, nodes or protuberances 12 extending from the cylinder head are preferably arranged in two or more concentriecircles about the spark plug 10, in equal spacing-of the bodies apart, as shown more particularly in Fig. 2,

while the corresponding elements 13 projecting from the piston head are similarly arranged but so spaced as to extend between the elements 12 as the pistonapproaches and completes its upward stroke as shown in Fig. 1. This arrangement of the respective elements 12 and 13 may be varied as desired, and one set of elements 12 or 13 may be omitted, although most desirably theV arrangement should be such as to present a substantially even distribution of the elements throughout the cubical contents of the combustion chamber in the advance position of the piston shown in Fig. 1.

In some cases also, and particularly where, as in some L-head engines, the spark plug is arranged in the lateral extension 6 adjacent the charge-inlet valve, the projections may be formed upon the upper Wall of the lateral extension G as well as upon the central portion of the cylinder head or on the piston or on both. Y,

The fins, nodes or protuberances described above and illustrated in Figs. 1 and 2, although extremely simple in design and structural arrangement, conform to the principles of my invention hereinbefore set forth and present the extended surface-contact means rer the charge, accelerating the reactions which occur in the gaseous phase in that charge upon compression and ignition thereof, and without increasing the normal heating effect of the compression stroke on the charge. The elongated elements 12 and 13, of relatively small mass or body, directly united throughout their maximum cross-sectional area, at their bases, with the cylinder head and piston, respectively, in fact very rapid-ly give up their heat to the larger masses of the cylinder wall and piston, so that their extended surfaces not only present the surface-contact means for an accelerating action on the charge but also present cooling sin-faces. looked at from the point of view of the maximum heat conditions normally present on the compression stroke in the conventional cylinder designs, and particularly when compared with the heat absorbing elements, vaporizing plates etc. of the prior art devices hereinbet'orc referred to. In this connection it may further be said, that while,

in the absence of other means accelerating the combustion reactions in the charge, the velocity of the reaction is greater at the higher temperatures, it has been found that the increase in velocity due to the accelerating effeet of surface-contact with the charge more than balances the diminution in velocity brought about by the lower temperatures produced by the cooling action of the surfaces.

Moreover, since the employment of an explosion chamber having the surface extensions described and shown will increase the velocity of combustion in a gasoline-air mixture, leaner mixtures than those now universally employed can be used and not only as quick acceleration attained thereby as with the' customary rich mixtures, but the extra heat losses due to the extended surfaces in the combustion chamber will be compensated for by the gain in heat liberated on ignition by the leaner mixtures in which combustion is more complete. In-other words, by my invention, the heat of compression is reduced `while the heat of combustion is increased,

the entire heat of combustion being liberated in a shorter time and the maximum combustion temperature being higher, thereby producing a greater initial pressure on the power stroke, with the desired effect of quick accelera-tion. Moreover, since on the compression stroke, the temperature of the charge is not as great as in the case of the conventional combustion chamber, because of the greater cooling effect of the larger surfaces employed in my invention, higher compressions'can be used and an all-round gain in power and eihciency of engine operation attained.

The fins, nodes or protuberances 12 and 13, also present the additional advantage of agitating the air and gasolene mixture as the piston nears the end of the compression stroke, causing a more thorough and uniform mixing of the air and fuel and assisting in the acceleration of the combustion reactions.

1. In an internal combustion engine employing a charge of gasoline and air, in combination with the combustion chamber thereof, surface-contact means for accelerating o o u the combustion reactlons in the gaseous phase in the charge, said means comprising a plurality of metallic lelements rigidly mounted within said combustion chamber and so distributed through the clearance space ot said combustion chamber as to present a substan- .tially even distribution or spacing of sepaof, surface-contact means for acceleratingI rality vof elongated metallic elements each mounted at one end on the interior head Wall ofthe cylinder in, spaced relation aboutv the axis of the cylinder to extend toward the piston head, and a plurality of like elements each mounted on the piston head inspaced relation about the cylinder axis to extend toward the cylinder head, said elements on said cylinder head and piston being of such length and so spaced as to overlap in the advanced position of the piston toward the cylinder head.

4. In an internal combustion engine of the type having a cylinder and reciprocating piston therein, employing a charge mixture of gasoline and air'and having a spark plug or the like ignition device Within the combustion space for initiating ignition for each power vstroke ofthe piston during 'operation of the engine; the combination with said cylinder, piston and ignition device, of means for modifying the combustion reactions in the gaseous phase in the charge initiated by the ignition device, said means comprisino metallic element means mounted to extend-)Within said combustion space and presenting surfaces in different planes spaced apart in a distribution of said surfaces beginning from points in immediate proximity to said ignition device toward the cylindrical side Wall of said cylinder, said distribution of said surfaces being such that the gaseous mixture at the moment of ignition is in contact with all of said surfaces in any plane through the clearance space of said cylinder transverse .to the cylinder axis.

5. In an internal combustion engine, in combination, a combustion chamber, a supply conduit to said chamber for a charge mixture of gasoline and air, an ignition device in said chamber for applying -an ignition spark to said charge mixture in the combustion chamber for each power strokeof the piston during the normal running of the engine, and metallic elements rigidly mounted to extend Within said combustion chamber with said 'elements presenting surfaces so. arranged chamber as to provide engagement with said surfaces of the gaseous charge upon compression and ignition thereof in any plane through the clearance space of said combustion chamber transverse to the cylinder axis, so, as to affect the propagation through that charge of the explosive Wave from its point of initiation by the ignition device.

6. In an internal combustion engine, in combination, a combustion chamber, a reciprocating piston therein, a supply conduit to said chamber for charge mixture of gasoline and air, an ignition device for applying an ignition spark to said charge mixture in the combustion chamber, and means for contacting the gaseous mixture with metallic surfaces at the time of the application of the ignition spark to accelerate the combustion reactions initiated by said spark, said means comprising metallic elements so mounted to extend into said combustion chamber as to present surfaces so distributed through the cubical contents of the clearance space thatany plane through said clearance space transverse to the Cylinder axis intersects a plurality of said surfaces.

7. In an internal combustion engine, in combination, a combustion chamber, a piston reciprocating therein, a supply conduit to said chamber for a chargemixture of gasoline and air, an ignition device for applying an ignition spark to said charge mixture in the combustion chamber and means for contacting the gaseous mixture with metallic surfaces at the time of the application of the ignition spark to accelerate the combustion reactions initiated by said spark. said means comprising metallic elements rigidly mounted to extend into said combustion chamber and presenting surfaces so spaced and distributed through-the cubical contents of the clearance space that the gaseous mixture at the time of the ignition contacts with said surfaces inwardly of the cylinder Walls and piston in all planes through said clearance space transversely of the cylinder axis.

In testimony whereof I hereunto affix my signature.

' CLARKE C. MINTER. 

